Should I Eat Before I Run? How to Fuel Your Body for Any Running Workout

Some runners can’t walk out of the door for a morning run without having something to settle their stomachs. Others cannot have a bit of food in their stomach without causing stomach distress. The overarching theme of sports nutrition is “every athlete is different”.

That doesn’t specifically help you much, does it?

So, in this article I will try to make the decision of “to eat or not to eat” a little easier by laying out arguments for and against eating before a run as well as what and when to eat it to set yourself up for a great workout.

Eating for different types of runs

In a typical week for me, there are 3 types of runs to consider: easy/recovery runs, long runs, and workouts.

Easy/recovery runs are at a comfortable, conversational pace and usually don’t last longer than 60 minutes.

Long runs vary by pace and are longer than 90 minutes.

Workouts are shorter in duration but higher in intensity than the other two types of runs.

Each type of run is associated with different fueling needs and different physiologic responses. I’ll get into the specific fueling needs of each run later in this article, but it’s important to make sure we’re all on the same page in regards to terminology.

Reasons for having something to eat before a run

• Liver glycogen, which maintains a normal level of blood sugar, can be depleted overnight. A small amount of food before exercise will increase your blood sugar and help prevent hypoglycemia, which could cause lightheadedness, blurred vision and fatigue.

• Food also helps settle your stomach and absorb some of the stomach juices that can cause discomfort, especially if you haven’t eaten in awhile.
• Finally, a pre-exercise snack is a last chance to fuel your muscles. Food eaten far in advance of a workout will be stored as muscle glycogen, but food eaten in the hour before exercise can be used as instant fuel if the exercise intensity is low enough to still allow for digestion.

Possible reasons not to eat before a run

• It is a common belief that exercising on an empty stomach will enhance the body’s use of fat as a fuel source, allowing one to burn more body fat. While this is true, understand that burning body fat to fuel exercise does not necessarily mean that one will lose body fat overall.To lose body fat, you still need to have an overall calorie deficit by the end of the day. If exercising on an empty stomach just sets you up to eat more later in the day than you would have if you ate before running, then there is no benefit.Also consider the fact that a small snack before may allow you to exercise harder and run longer, which would result in burning more calories.

• Fears of getting an upset stomach, diarrhea, or just feeling sluggish are other reasons why one might choose not to eat before exercise. Avoiding foods that are known to cause distress and eating the right kinds of foods can resolve these issues. Also, getting an adequate amount of food the day and night before a morning workout will decrease your need to eat much in the hours before.

What to eat before each type of run

Now you know the arguments for and against eating before a run. The next questions to consider are the intensity of the run and the timing of the run.

The body’s ability to digest a recent meal depends on the intensity of the workout. If the pace is generally easy and is something you could easily keep up for 30 or more minutes, then your body should still be able to digest a recent meal or snack and use it for fuel. If you need some pre run snack ideas, we’ve written a great article on how to find the optimal time to eat and what to eat before a run.

The more intense a workout is, the more blood flow will be shifted away from the stomach and to the muscles, decreasing the body’s ability to digest. Therefore, more planning needs to go into pre-workout meals as compared to meals before easier runs.

Now let’s consider the timing of workouts

Morning workouts

As mentioned before, liver glycogen can be depleted overnight and you may wake with low blood sugar. Care should be taken in the day and night before a workout to make sure muscle glycogen stores are full. However, a small snack before a workout can help bring your blood sugar back up and maintain normal levels.

A general rule of thumb is to eat about 0.5 grams of carbohydrate per pound of bodyweight up to one hour before a workout. For a 150 pound runner that would be 75 grams, or 300 calories worth of carbohydrate. This carbohydrate load can be achieved through a combination of solid and liquid carbohydrate, such as a bowl of cereal and 1 or 2 cups of sports drink. The sooner you eat the better so that the body has ample time to digest before an intense workout.

Afternoon or evening workouts

Afternoon and evening workouts give you more time to fuel your body with good carbohydrates and adequate amounts of fluids. It is important on these days to start off with a good breakfast and continue on with a healthy lunch 3-4 hours before the workout.

Choose foods that are high in carbohydrate, moderate in protein, and low in fat. Fats and proteins delay gastric emptying. Focus on complex carbohydrates for a sustained source of energy, but avoid very high fiber foods.

Bottom line

Tolerances vary from person to person so you have to use trial and error to find out what foods work for you and if you exercise better with having something to eat.

My recommendation would be to have something to eat before long runs and workouts so that you can get the best training effect out of your run. Easy and recovery runs do not require pre-exercise foods most of the time, just be sure to fuel your body well throughout the day for your workouts later in the week.

Final tips for eating before a run

• Eat adequate, high-carbohydrate meals on a daily basis so that your body is always ready for a run or workout.

• For longer runs (more than 60 minutes), choose slowly digested carbohydrates like yogurt, apples, bananas, and oatmeal. Also consider similar foods for fueling during the long run.

• Avoid sugary foods like soft drinks, candy, and sugary gels that can quickly spike the blood sugar and actually lead to hypoglycemia.

• The more calories you eat, the more time you need to give your body to digest, especially before intense workouts.